A camshaft module is known, for example, from DE 10 2011 111 580 A1. The camshaft module has a module body, and the module body is substantially constructed from a hood and from a number of bearing bridges for rotatably accommodating two camshafts. A plurality of actuators which, upon appropriate activation, can axially adjust the sliding cam pieces shown on a support shaft are accommodated in the hood. The hood of the module body is generally formed from aluminum or from a special plastics material. By contrast, the camshaft comprises a steel material, and therefore coefficients of thermal expansion which differ from one another arise for the material of the module body and for the camshaft. However, for reasons of lightweight construction, the module body is preferably produced from aluminum or from a special plastic, and, for technical reasons, in particular for strength reasons, the at least one camshaft accommodated in the module body, in particular the support shaft, is produced from a steel material.
During use of a camshaft module in an arrangement on an internal combustion engine, a pronounced difference in temperature of the camshaft module can be achieved depending on the operating state. For example, when the internal combustion engine is started up, a temperature of −40 degrees can prevail, and, at high load ranges of the internal combustion engine, the camshaft module can heat up to, for example, up to 150 degrees.
On account of the differing coefficients of thermal expansion of the camshaft, in particular the support shaft, and the module body, dimensional deviations in the position of the actuators relative to the positions of the sliding cam pieces can arise in the axial direction. The actuators have actuator pins which, upon activation of the actuators, engage in slotted guides which are provided on the outer side in the sliding cam pieces. Depending on arising operating temperatures of the camshaft module, different thermal expansions of the module body and the camshaft may mean that secure engagement of the actuator pin in the slotted guide is ensured. Thermally induced deviations in the position of the actuator pin relative to the position of the slotted guide can be up to 0.5 mm, in particular depending on the overall length of the module body in the axial direction, and therefore, in particular when further tolerances are accumulated, the function of the axial adjustment of sliding cam pieces of the camshaft is no longer ensured, and increased wear of the camshaft module can arise.
DE 10 2011 088 994 A1 deals with a valve drive for the cylinder head of an internal combustion engine, wherein the pickup side is described for picking up the stroke information from the camshaft via pivot lever and roller element. The valve drive comprises a shaft support in which a camshaft and eccentric shaft are mounted. It is stated here that the support element and the cylinder head are formed from an identical material, for example from light metal material, such as aluminum. As a result, materials comprising approximately identical coefficients of thermal expansion are paired with one another in order to avoid thermal stresses between the support element and the cylinder head. The same selection of material for the support element and the cylinder head is technically possible here, but this technical possibility, as described above, is not possible for the camshaft module of the present type.